Metabolites of sphingomyelin, sphingolipids such as ceramide, sphingosine or sphingosine 1-phosphate, participate in intracellular signal translation, such as apoptosis, cell proliferation, PKC inhibition, etc., and therefore the metabolites have drawn the great attention. From the fact, the enzyme, sphingomyelinase which converts sphingomyelin to ceramide is considered to be a very important enzyme.
However, the mechanism of action and the higher-order structure of this enzyme are not elucidated and therefore, such a substance as useful for a resolution of the mechanism, etc., has been desired.
The present inventors designed photoaffinity-labeled sphingomyelin analogs and prepared them in order to investigate the mechanism of action of sphingomyelinase. The result of the study was reported on the 33rd Symposium of Heterocyclic chemistry (See the abstract of the 33rd Symposium of Heterocyclic chemistry, page 42-43, issued on Sep. 19, 2003). However, the compounds disclosed therein are sphingomyelins having a photoaffinity-labeled group at their main chain or their N-terminus of the acyl group, and the photoaffinity-labeled group is hydrophobic. The group is quite separated from the phosphate, and therefore it is not considered that such compounds are most suitable for resolution of the mechanism. Therefore, the development of the compound which is useful for more effective resolution of the mechanism of sphingomyelinase has been desired.